The Microwave Temperature Sounder

the Microwave Humidity Sounder and the Microwave Radiation Imager were flown on the new-generation polar satellite FY-3A in China.The microwave sensors’ calibration after launch is a critical problem.Using the SSM/I data

and the surface and raob observations

the stability of microwave emissivity in Simao Yunnan is analyzed based on the microwave modeling in this article.The results show that its vegetation situation is very good

and the surface microwave emissivity is stable.The surface microwave emissivity has weak season-to-season variation in law of sines（the changing range is less than 0.02）.It also has very small year-to-year difference

which can be corrected by modeling based on the surface and raob observations.